Vehicle manufacturers have continuously faced the challenges of vehicle collisions and the crash violence that such vehicle collisions may impart on the vehicle. Side impact protection system SIPS was one way of significantly improving the safety for passengers in vehicles. By introducing chassi beams underneath the vehicle seats and the dash board, the risk of side collisions could be significantly reduced. Air bags deployed at selected strategic positions gave additional protection to the passengers.
There are still needs however to continuously increase passenger safety. One way to provide additional safety to passengers is to provide improved vehicle seats. Generally, vehicle seats today have relatively stiff cross tubes, also referred to as cross brace or cross members. However cross members may deform unpredictably which could accidentally injure passengers or structural features of the vehicle or vehicle systems.
One attempt to provide a predictable deformation is disclosed in the published U.S. Pat. No. 6,523,893 B2 in which a vehicle seat having a cross brace intended to deform and bend in a predetermined way. The deformation is performed in two steps. Firstly; the cross brace is telescopically retracted as a function of the impact force and secondly; the cross brace bends in a predetermined way by use of notches. The solution is said to minimize danger of injury to the vehicle passengers. The disclosed solution is however not very attractive as it is a two-step procedure. Furthermore, the proposed solution requires the cross-brace to be manipulated by addition of corrugations which is costly and relatively difficult as tolerances of multiple components may need to fit with each other.
Another but different attempt at deal with side collisions is disclosed in the U.S. Pat. No. 8,182,026 B2 in which a cross member is made less strong but with the addition of an adjusting element arranged in the force path. The force adjustment element is intended to dissipate a considerable part of the force exerted in the event of a motor vehicle crashing by energy absorption via elastic, plastic and/or collapsing deformation. By means of a spring, the forces exerted may be absorbed. The just mentioned solution is directed to absorb the force exerted which in practice is very difficult. The force adjustment element may be partly formed by a spring, and a spring may be too stiff or too soft dependent on the exerted force.
Vehicle seats having relatively stiff cross tubes may rely on the fact that the vehicle seat may be displaced a limited distance so as to absorb some of the force exerted on the vehicle seat during a collision. However, due to the more frequent use of electric vehicles, the space between vehicle seats has become more limited or better used. The space between vehicle seats is sometimes referred to the tunnel area. In recent years, the space defined as the tunnel area has been consumed by battery storage in some vehicles. Hence earlier rigid cross members relying on the displacement of the vehicle seat may not be a sufficiently good solution any more. Further, batteries are very sensitive for intrusion of foreign objects as battery elements may be harmed during a collision. When using Lithium-ion batteries, intrusion of foreign objects may short circuit the batteries overheating the batteries with consequently increase the risk for fire.
The above mentioned solutions are expensive and in some cases even difficult to manufacture so as to get a predictable result. There is thus a need for a solution which provides large amount of varieties without adding significant costs and which is still easy to manufacture. A solution that provides a predictable result and which adds to the safety of the passengers.